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Kawamura, Takuma; Idomura, Yasuhiro
Journal of Visualization, 23(4), p.695 - 706, 2020/08
Times Cited Count：1 Percentile：7.62(Computer Science, Interdisciplinary Applications)An in-situ visualization system based on the particle-based volume rendering offers a highly scalable and flexible visual analytics environment based on multivariate volume rendering. Although it showed excellent computational performance on the conventional CPU platforms, accelerated computation on the latest many core platforms revealed performance bottlenecks related to a function parser and particles I/O. In this paper, we develop a new SIMD-aware function parser and an asynchronous data I/O method based on task-based thread parallelization. Numerical experiments on the Oakforest-PACS, which consists of 8208 Intel Xeon Phi7250 (Knights Landing) processors, demonstrate an order of magnitude speedup with keeping improved strong scaling up to 
100 k cores.
Kawamura, Takuma; Idomura, Yasuhiro; Miyamura, Hiroko; Takemiya, Hiroshi
Journal of Visualization, 20(1), p.151 - 162, 2017/02
Times Cited Count：3 Percentile：18.26(Computer Science, Interdisciplinary Applications)In this paper, we propose a novel transfer function design interface for multivariate volume rendering. In the conventional multivariate volume rendering, GUI based transfer function design interfaces were limited to two-dimensional variables space. In order to design higher dimensional transfer functions in an interactive and intuitive manner, a Transfer Function Synthesizer (TFS) is developed. On the TFS, multi-dimensional transfer functions are generated by algebraic synthesis of one-dimensional transfer functions, which are designed based on the conventional GUIs or algebraic expressions. The TFS enables not only multivariate volume rendering but also general visualization techniques such as surface visualization and image composition within the framework of volume rendering. The TFS is implemented on the remote visualization system PBVR, and applied to various multivariate scalar volume data generated from nuclear applications.
Kawamura, Takuma; Noda, Tomoyuki; Idomura, Yasuhiro
Proceedings of 2nd Workshop on In Situ Infrastructures for Enabling Extreme-scale Analysis and Visualization (ISAV 2016) (Internet), p.18 - 22, 2016/11
Times Cited Count：9 Percentile：90.83(Computer Science, Interdisciplinary Applications)A novel in-situ online visualization framework is developed based on the Particle Based Volume Rendering (PBVR), which renders multivariate volume data using view-independent particle data. Our online approach enables visualization of particle data with interactive view exploration and changes of multi-dimensional transfer functions at runtime. The runtime visualization show excellent strong scaling up to thousands of cores, and its computational cost is small. These features enable flexible in-situ data exploration for monitoring extreme scale simulations. The utility of the proposed framework is demonstrated by applying it to simulations of molten debris relocation in reactor pressure vessels using the JUPITER code.
Hoshi, Yoshiyuki; Kume, Etsuo
JAERI-Data/Code 2005-010, 48 Pages, 2005/09
JAERI-Data-Code-2005-010.pdf:8.7MB
In scientific and engineering calculations, recently, computational sizes and amounts of calculated results have been increased rapidly due to speedup of computers and increase in memory size. Post processing or visualization of a huge amount of numerical data plays a very important role for understanding the meaning of the data. Computational loads for visualization of large-scale data are still heavy even for graphic computers. Processing speeds for visualization of large-scale data are measured using general-purpose visualization software on graphic computers in JAERI. A guideline is summarized in this report to choose appropriate graphic computers according to the size of the data.
Suzuki, Yoshio*; Takeshima, Yuriko; Ono, Nobuaki*; Koyamada, Koji*
Nihon Bacharu Riaritei Gakkai Rombunshi, 10(2), p.231 - 240, 2005/06
A volume rendering is widely used for intuitively understanding 3-dimensionaly distribution of physical quantities. When the quantities have a nest-like distribution, however, the inside distribution cannot be observed. As one of the solution, an immersive virtual reality (VR) system is useful, since the researcher can immersively observe the distribution by using such a system. However, a plane slice sampling method conventionally used in the volume rendering has a problem that the quality of visualized images deteriorates especially in the immersive VR system. To resolve the problem, a spherical surface sampling method is applied to the volume rendering in the immersive VR system. The quality of image and the display speed are compared between these two methods.
Nakajima, Norihiro; Ono, Nobuaki*; Suzuki, Yoshio*; Kureta, Masatoshi*
Denki Gakkai Rombunshi, C, 124(10), p.2197 - 2198, 2004/10
Our research interest is to implement volume rendering on CAVE system at enough frame rate. It can be implemented on CAVE easily using texture mapping but there are some defects; for example frame rate declines when the view point is close to the data and images projected to the screens become big. Thus we try to find another way to implement it on CAVE. Considering that Onyx300 is a parallel computer and there are some algorisms of volume rendering which improve the frame rate, we make the program that draws stereo images through two of the algorisms and by parallel computing, and displays only two images on CAVE. And we confirm that this program works well and draws stereo images at sufficient frame rates.
Suzuki, Yoshio; Sai, Kazunori*; Ono, Nobuaki*; Koyamada, Koji*
Kashika Joho Gakkai-Shi, 24(Suppl.1), p.443 - 446, 2004/07
no abstracts in English
Ono, Nobuaki*; Suzuki, Yoshio; Kureta, Masatoshi
Kashika Joho Gakkai-Shi, 24(Suppl.1), p.315 - 316, 2004/07
no abstracts in English
Takeshima, Yuriko; Takahashi, Shigeo*; Fujishiro, Issei*
Visual Computing/Gurafikusu To CAD Godo Shimpojiumu 2004 Yokoshu, p.37 - 42, 2004/06
no abstracts in English
Kawamura, Takuma; Idomura, Yasuhiro; Miyamura, Hiroko; Takemiya, Hiroshi
no journal, ,
In visualizing large-scale data on remote strage, existing remote visualization tools have bottlenecks in the processing speed, the memory size, and the data transfer. Client/Server visualization system using Particle-based volume rendering resolves these bottlenecks by converting large-scale data into small visualization particles. We developed this system for supercomputer and tuned particle generation process for the parallel distributed environment. Our system achieved strong scaling with high parallel efficiency over 90%.
Kawamura, Takuma; Idomura, Yasuhiro; Miyamura, Hiroko; Takemiya, Hiroshi
no journal, ,
Client-Server type remote visualization system using Particle-Based Volume Rendering (PBVR) efficiently visualizes large-scale data located on remote supercomputer system. Multi-dimensional (2D) transfer function is efficient technique to extract the munite structure using a physical value and its absolute value of gradient. We extended the multi-dimensional transfer function to extract any slice surface of iso-surface for multi-variate data and developed PBVR particle generation method for multi-dimensional transfer function, which enables to treat multi-variate data on supercomputer. We applied this technique to the result of numerical simulation for relocation behavior of molten debris in nuclear reactor, and extract the forms of the molten debris and mapped thermal distribution.
Kawamura, Takuma
no journal, ,
I present the research result of "Remote Interactive In-Situ Visualization using Particle Data for Volume Visualization" supported by the Joint Usage/Research Center for Interdisciplinary Large-scale Information Infrastructures (JHPCN), 2017. With the increase of simulation scale, the conventional visualization process involving data transfer to the pre-post node requires a huge processing cost. To enable real-time visualization and analysis of large-scale simulations, an interactive In-Situ visualization system using particle data for visualization is optimized for the latest SIMD platforms such as XeonPhi, and FX100. Using this system, interactive visualization at runtime is enabled for batch processing simulations.
Kawamura, Takuma; Sakamoto, Naohisa*
no journal, ,
The visualization library KVS is equipped with various visualization methods and is used by domestic and foreign researchers. Particle-Based Volume Rendering (PBVR), which is implemented in KVS, does not require sorting computation in alpha blending and has advantages in parallel visualization for large-scale data. In this study, we extended the functionality of the visualization library KVS, including PBVR, for the Oculus head-mounted display, and built a client-server remote VR visualization application as a use case.
